# Problem with array

I'm having some errors while copmiling the following:

$$k_{t+1}=\left\{ \begin{array}{l} A.s.k_{t}^{\alpha}+(1-\delta).b_{t}^{P}-\delta.b_{t} \quad \text{if \frac{b_{t}+b_{t}^{P}}{(1-\epsilon).s.k_{t}^{\alpha}} < 1} \\ s.k_{t}^{\alpha}-b_{t} \quad \text{if \frac{b_{t}+b_{t}^{P}}{(1-\epsilon).s.k_{t}^{\alpha}} \geq 1} \end{array} \right.$$


## Notes:

• Not sure what the . means in your equations, but did you perhaps intend to use a \cdot?

• Your cases example in the comments had an extra & at the end. I have added that example in the MWE.

## Code:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
$$k_{t+1}=\left\{ \begin{array}{l} A.s.k_{t}^{\alpha}+(1-\delta).b_{t}^{P}-\delta.b_{t} \quad \text{if \frac{b_{t}+b_{t}^{P}}{(1-\epsilon).s.k_{t}^{\alpha}} < 1} \\ s.k_{t}^{\alpha}-b_{t} \quad \text{if \frac{b_{t}+b_{t}^{P}}{(1-\epsilon).s.k_{t}^{\alpha}} \geq 1} \end{array} \right.$$

$$k_{t+1}= \begin{cases} A.s.k_{t}^{\alpha}+(1-\delta).b_{t}^{P}-\delta.b_{t} & \quad \text{if } \frac{b_{t}+b_{t}^{P}}{(1-\epsilon).s.k_{t}^{\alpha}} < 1 \\ s.k_{t}^{\alpha}-b_{t} & \quad \text{if } \frac{b_{t}+b_{t}^{P}}{(1-\epsilon).s.k_{t}^{\alpha}} \geq 1 \end{cases}$$
\end{document}